<template>
  <div class="blog-comment-container">
    <MessageArea
      @submit="handleSubmit"
      title="评论列表"
      :subtitle="`(${data.total})`"
      :list="data.rows"
      :isListLoading="isLoading"
    />
    <Empty v-if="data.rows.length === 0 && !isLoading" />
  </div>
</template>

<script>
import MessageArea from "@/components/MessageArea";
import fetchData from "@/mixins/fetchData.js";
import { getComment, postComment } from "@/api/blog.js";
import Empty from '@/components/Empty';
export default {
  mixins: [fetchData({ total: 0, rows: [] })],
  components: {
    MessageArea,
    Empty,
  },
  data() {
    return {
      page: 1,
      limit: 10,
    };
  },
  created() {
    this.$bus.$on("mainScroll", this.handleScroll);
  },
  destroyed(){
    this.$bus.$off("mainScroll",this.handleScroll);
  },
  computed: {
    hasMore() {
      return this.data.rows.length < this.data.total;
    },
  },
  methods: {
    //在一定范围内触发fetchMore事件
    handleScroll(dom) {
      if(this.isLoading || !dom){
        //如果正在加载中
        return;
      }
      //区间范围
      const range = 100;
      const desc = Math.abs(
        dom.scrollTop + dom.clientHeight - dom.scrollHeight
      );
      if (desc <= range) {
        //到达底部
        this.fetchMore();
      }
    },
    async fetchData() {
      //传入id从博客路由地址里面获取
      return await getComment(this.$route.params.id, this.page, this.limit);
    },
    async fetchMore() {
      if (!this.hasMore) {
        //没有更多了
        return;
      }
      this.isLoading = true;
      this.page++;
      const resp = await this.fetchData();
      this.data.total = resp.total;
      this.data.rows = this.data.rows.concat(resp.rows);
      this.isLoading = false;
    },
    async handleSubmit(formdata, callback) {
      const resp = await postComment({
        blogId: this.$route.params.id,
        ...formdata,
      });
      this.data.rows.unshift(resp);
      this.data.total++;
      callback("评论成功！");
    },
  },
};
</script>

<style scoped lang="less">
.blog-comment-container {
  margin: 30px 0;
}
</style>